Parkinson’s Disease and Cognitive Impairment |

We all know the standards symptoms of Parkinson’s disease (some 500,000 in the US alone) patients- tremors, slow motion, etc. But, most of us fail to recognize these patients also suffer from cognitive impairment. They don’t lose their memory- they just can’t make decisions, plan, or adequately control their emotions

The standard symptoms are related to decreased dopamine levels in the brain; the administration of L-Dopa, therefore, alleviates these symptoms. One would think that dopamine would assist in cognition (it is decreased in cognitive portions of Parkinson’s disease patients)- but it doesn’t. It is possible that this (cognitive loss) is more a function of a deficit in the number of dopaminergic neurons.

For years, physicians assumed that Parkinson’s sufferers were also suffering from Alzheimer’s. But the amyloid protein plaques that are characteristic for Alzheimer’s are different that those found in Parkinson’s patients, who have protein deposits called Lewy bodies. This is comprised of alpha-synuclein (a protein), as well as ubiquitin, and neurofilament proteins. among other items. However, by examining the CSF (cerebrospinal fluid) of patients, Dr. Thomas Montine (lead researcher, University of Washington) found that almost 50% of the dementia-Parkinson’s patients and 1/3 of those cognitive impairment-Parkinson’s patients had indications of amyloid plaques (decreases amyloid in the CSF). As such, he believes that the same therapies provided Alzheimer’s may benefit these Parkinson’s sufferers.

Dr. Montine is searching for a test to indicate the presence of Lewy bodies (in live patients). That would afford earlier treatment for Parkinson’s disease. The initial efforts involve testing the CSF of Parkinson’s patients who died and had Lewy bodies present. Right now, they are focusing on alpha-synuclein (the primary protein in the Lewy body) as a marker.